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How to get evaporator pan tablets in Mitsubishi mini-split indoor unit drain pan

allenm Member Posts: 7
I thought this was going to be simple, since various online videos and help guides show just pulling the filters and dropping the tabs in the drain pan. But my new 2023 Mitsubishi wall units have no such openings big enough. I think these models came out about 2 years ago. MSZ-FS06NA-U1 / MUZ-FS06NAH-U1 in the master bedroom and a MSZ-FS18NA-U1 / MUZ-FS18NAH-U1 in the living room area.

It looks to me like I would have to completely remove the wall cabinets in order to drop the pan down a little to get the tabs inside. That is ridiculous! Sounds like a way to prevent homeowners from doing even simple maintenance,

Anyone have any ideas or experience with these models?


  • pecmsg
    pecmsg Member Posts: 4,201
    allenm said:
     That is ridiculous! Sounds like a way to prevent homeowners from doing even simple maintenance,
    Maybe contact Mitisubishi. 
    I’ve never had to use tabs 
  • allenm
    allenm Member Posts: 7
    I don't want to use tabs, unless it's a good idea. I got the impression they can prevent mold, algae, gunk from building up in the tray and drain hose. I'm still deciding on whether to go with a maintenance agreement or try to keep them clean myself. If the tabs really work that could make things easier for me. I know the tabs can't do anything for buildup on the coils and blowers. They are only 3 months old, so no bad stuff yet.
  • pecmsg
    pecmsg Member Posts: 4,201
    edited September 12
    A properly sized and installed system does not need them. 
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 6,142
    edited September 13
    Every three to five years you will get enough dust build up on the coil and fan that will require a invasive cleaning. Even the cleanest homes are not immune to mold accumulation on a damp dusty surface. I purchased a maintenance kit that comes in a 5 gallon pail. In the pail was a pump with some hoses, a bottle of cleaning chemical and this plastic sheet that was stuffed behind the wall hung indoor unit and a bracket that formed a large funnel to collect any over spray and drain pan overflow. The funnel shaped sheet of plastic would reduce down to a 2" diameter drain that would terminate in the bucket.

    As you pumped the cleaner into a spray nozzle the pressure would "pressure wash" the dirt off the coil and wash the dust build up into the drain pan. The amount of liquid sprayed would overwhelm the drain pan and overflow into the plastic sheet funnel and end up in the 5 gal pail. Set up and spray cleaning would take about 1 hour. Take the air filters outside or the laundry tub to clean and rinse them. Put the indoor unit back together and wipe down the cabinet took another 30 minutes. From start to finish, tools packed up in the van, total time 2 hours.

    Get 4 done a day. This kit paid for itself within the first 3 weeks, all you need is a picture of all the gunk and mold inside the unit and quote a price for job. Then schedule a day of "Deep Cleaning" services for next week. (Make even more if there are 2 or more units in the same home).

    Look at the video on this product for a visual.

    You could purchase one for your own use or you could find a HVAC maintenance company that owns one and have them stop by every so many years. Tablets will only keep the pan clean (Maybe). The rest of the parts are going to get dirty. There's no getting around it!

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • allenm
    allenm Member Posts: 7
    Thanks Ed. That was helpful. I've pretty much decided to have a pro come in for a indoor unit cleaning when I can see excessive buildup on the cooling fins and blower vanes. I could do it myself but for some reason I keep getting older (77 at present) and find my capabilities keep getting reduced. But I should be able to do the outside unit cleaning myself.